Automatic firearm



May 23, 1939. M, B|RK|GT AuTormrc FIREARM Filed April le'. v19:58

Patented May Z3, i939 MEME? 2,159,127 an'rom'ric mmm/r Marc Birkigt, Bois-Colombes, France Application April 16, 1938, Serial No. 202,547 In Belgium February 17, 1938 5 Claims.

The present invention relates to automatic rearms and especially light guns to be mounted on aircrafts.

The type of gun with which the present invention is concerned includes a breech structure, movable at the rear of the gun tube, under the opposed actions of the recoil produced by each shot and of a counterspring. IIfhis breech structure includes two parts adapted to move relatively to each other to a limited extent, one of said parts constituting the breech block proper and .the other the firing pin carrier.

A pawl is pivotally carried by the breech block and it is adapted to cooperate with the firing pin carrier in such manerv as to interlock these two breech structure elements as long as the breech block has not reached its extreme position toward the front, which corresponds to the closing of the rear end of the gun tube. 'I'his pawl is adapted to disconnect these two breech elements when the breech block reaches this extreme position, and simultaneously to lock the breech block in fixed position with respect to the gun casing.

Therefore, when the breech block is thus stopped the ring pin carrier is allowed further to move in the frontward direction under the action of the counterspring, so that the firing pin strikes the cartridge in the known manner.

In some guns of this type, the pawl above mentioned (pivoted to the breech block) cooperates with the other breech element (ring pin carrier) through contacting surfaces which are oblique to the direction oi the thrust transmitted from said pawl to said ring pin carrier, and vice versa.

Therefore a reaction is produced which has a component tending to move said pawl transversely away from the cooperating surface of the ring pin carrier. This transverse component is without eiect as long as the pawl is moving (together with the breech block) along a fixed guiding surface which prevents this transverse movement. But when the breech block reaches its extreme position toward the front, corresponding to the closing of the rear end of the gun tube, said pawl comes opposite an aperture in said guiding surface. Under the eiect of the above mentioned component the pawl engages into said aperture, or behind a stop, so that, on the one hand, the breech block and the ring pin carrier arev -uncoupled, and, on the other hand, the breech block is locked in its extreme front position with respect to the xed casing of the gun.

In other types of guns, the movement of the pawl which simultaneously produces the uncoupling of the two breech structure elements and the locking of the breech block with respect to the breech casing, instead of being produced by the transverse component above mentioned, is produced by the cooperation of a' stop carried in xed position by said casing with a corresponding stop carried by the pawl, these two stops coming into contact with each other at the end of the frontward movement of the breech block.

Both of these arrangements have 'disadvantages.

In guns of the rst mentioned type, as the component force which tends to move the pawl transversely exists during the whole movement of the breech structure, it may happen that when the pawl comes opposite the aperture in the xed casing into which it is to engage under the action 'of said component force, its transverse displacement is delayed by jamming. This delay may cause the stopping of the operation of the gun or at least a substantial reduction oi the number of shots red per unit of time.

In guns of the second mentioned time, as the two stops provided on the pawl and the casing of the gun strike each other more or less violently, there is a possibility of rebounding of said pawl, which involves serious jolts in .the operation of the gun, leading to a rapid wear and tear of the pawl and of the parts cooperating therewith.

The object of the present invention is to provide a gun construction which avoids these various drawbacks.

According to the essential feature of the pres-` ent invention, I employ simultaneously and in combination, cooperating inclined surfaces on the breech block pawl and the firing pin carrier and cooperating stops carried by seid pawl and the xed breech casing. With such an arrangement, when said pawl is to pass from the position in which it couples the two breech elements together to the position in which it locks the breech block with the breech casing (while simultaneously disengaging said two breech elements from each other) this movement of the pawl is positively controlled by a double action (resulting, on the one hand, from the transverse component of the thrust transmitted from the ring pin carrier to the breech block proper, and on the other hand from the direct action of the stationary stopl of the breech casing on the stop carried by the pawl) so that it is possible to make use of one of these actions for starting at the exact time the desired movement of the pawl and of the other action for preventing the reboundingof said pawl.

Other features of the present invention will result from the following detailed description of some specic embodiments thereof.

A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawing, given merely by way of example, and in which:

Fig. 1 is an elevational view, partly in axial vertical section and partly in section on the line I-I of Fig. i3, of the breech mechanism of an automatic gun for an airplane, made according to the present invention;

Fig. 2 is a view, similar to Fig. 1, showing the same mechanism with another relative position of the parts, corresponding to another period of the operation of the whole; l

Fig. 3 is a sectional viewvon the line III-III of Fig 1;

Fig. 4 is a vertical section on the line IV-IV of Fig. 1;

Fig. 5 is a partial vertical section on the line V-V of Fig. 1;

Figs. 6 and 7 are detail views showing, on a larger scale, characteristic relative positions of some elements of the structure of Figs. 1 and 2.

In the construction illustrated by the drawing, the barrel or tube I of the gun is provided, at its lower end, with a breech casing adapted to accommodate a slidable breech structure. This casing 2 is provided at the top with a cartridge feeding slot 3 and at the bottom with an ejection slot 4 for the cartridge cases.

The breech structure slidable in said casing .2 is urged toward the front position thereof by a counterspring 5. This breech structure includes two main elements 6 and 'I, slidably mounted with respect to eachother in the direction of the sliding movement of both together in the breech casing. l

Breech element 6, which/ constitutes the breech block proper, serves to forceand wedge, through its front end, the cartridge into the gun chamber.

When. the cartridge is thus fully engaged and held in the gun chamber, the breech block 6 is in its extreme position toward the front, and this position will be hereinafter called firing position. 2

As for the other breech element, to wit ll, it carries the firing pin which is to strike the cartridge in the usual manner.

The breech block 6 carries a pawl 93 adapted to couple breech elements 6 and 'I with each other as long as element 6 is not in the firing position. 'I'his pawl and element 'I contact each other along surfaces which are so inclined with respect to the direction of the thrust transmitted from the one to the other that the pawl tends to be moved away from element I in a transverse direction by the reaction. But a guiding surface along which said pawl is slidable prevents this transverse displacement of the pawl until the end of the frontward movement of the whole, when the breech block 6 is reaching its firing position. At the same time, a fixed abutment, carried for instance by casing 2, also moves the pawl into the new position it is to occupy. The combined actions of said fixed abutment and of said cooperating inclined surfaces (of the pawl and the firing pin carrier l) cause the pawl to be suddenly switched into a position in which it ensures the locking of the breech block 6 with respect to the breech casing 2, while releasing element 'I from said breech block, whereby element 'I is thus allowed to move further under 5 the action of the counterspring 5, although the breech block is now immobilized.

I provide means for driving element 'i in the rearward direction immediately after the firing of a shot, so as to cause it` to come back into locking engagement with the breech block 6. This engagement coincides with the disengagement of the breech block 6 from the breech casing 2, and the whole is then moved toward the rear.

From this time on, the pressure f the burnt powder gases on the case of the cartridge that has been fired suffices to ensure the full recoil of the movable breech structure and the ejection of the spent cartridge.

'I'he breech structure constituted by the assembly of the breech block' proper 6 and of element I is advantageously given an external shape (for instance rectangular as shown by Fig. that it fits in casing 2 in a slidable manner.

Elements 6 and I are further mounted relatively to each, other in such manner as to permit a slight relative axial displacement of said parts with respect to each other as above explained, elastic means, such as springs 1', being advantageously interposed between said elements in such manner as constantly to urge element I toward the front end of the re arm with respect to element 6.

For instance, as shown by the drawing, element 'I is so designed as to surround at least partly the breech block, said element 'I being provided, at the front end thereof, with a cross member 9 the central part of which carries a plug' I0 the front part of which is fitted with the firing pin 8. The counterspring 5 above mentioned, which is housed in an axial cavity II of the breech block 6, bears upon the rear face of said plug I0, so as to push it frontwardly;

The breech block 6 is provided with a transverse slot I2, elongated in the axial direction of the firearm, so as to be longer than the longitudinal section of cross member 9. The limited displacement between elements 6 and I results from the difference of size between said member andsaid slot, or, in other words, from the play of member 9 'in slot I2.

'I'he side walls of element 'I are further provided with housings 'I' for the springs r above mentioned, each of said springs being interposed between one end of the corresponding slot l' and a corresponding lug b rigid with the breech block 6 and adapted to slide in said slot I when elements 6 and l of the breech structure move with 'respect to each other.

In this embodiment of my invention, the locking means above described in a general manner are made as follows:

The pawl i3 above referred to is pivoted, at its front end, to the breech block 6, and its rear end is provided with a head I4.

The breech casing 2 is provided with an aperture or notch I5 into which said head I4 can engage when the breech block reaches its ring position. Ihe contacting faces I4' and I5 of said head and said notch respectively are, for instance, such that a thrust in the rearward direction exerted by the breech block on the breech casing cannot cause the head I4 to disengage itself from notch I5. For this purpose, said cooperating faces I4 and I5 are given the proper inclination with respect to the direction of the thrust (see Figs. 1 and 2).

Pawl i3 and element 'I are provided with coacting inclined surfaces, such as I6 and Il, adapted, when element l is moving in the rearward direction with respect to the breech block 6, of causing head I4 to be disengaged from notch I5.

I provide, onelement l, a surface I8 adapted to prevent head I4 from leaving notch I5 as long as element l is in front position with respect to the breech block 6, said surface I8 cooperating with the top edge of a notch provided in head Il.

Pawl I 3 and the breech casing 2 are provided with respective linclined vsurfaces 26 and 2l adapted to cooperate/with each other in such manner that, when the whole of elements 6 and 'I is moving toward the front, near the end of this displacement, these cooperating surfaces'A bring pawl I3 into a position, hereinafter called lower position, in which head I4 is disengaged from the notch I9 of element 'I and on the contrary engaged into notch I5, inclined surface being preferably mounted laterally -on pawl I3.

In accordance with the principle of the present invention, the movement of pawl I3 into engagement with notch I5 (from the position of Fig. 'I into the position of Fig. 6) instead of being started merely by the cooperation of inclined surfaces 2l) and 2I (carried by the head of the pawl and by the breech casing) is also produced as a consequence of the thrust transmitted by element 'I to the breech block 6 through pawl I3.

Consequently, head IB and the inner wall of notch i9 are provided with respective inclined surfaces I li" and I9" adapted to cooperate with each other so that near the end of the return stroke of the whole of the movable breech structure toward the front, the thrust transmitted from one of said inclined surfaces to the other produces a transverse component, corresponding to the downwardly directed force F, which tends to push head Id into notch I5 as soon as said head comes opposite said notch.

Thus, as soon as, in the course of the frontward movement of the whole of the breech structure, said head-i5 is brought above notch I5, it is driven into said notch bythe combined action of cooperating inclined surfaces 20 and 2l on the one hand and cooperating inclined surfaces I4" and I9" on the other hand. In some cases, surfaces I" and I9 may start the downward pivotg ing movement of pawl I3 before inclined surfaces 2B and 2l havef come into contact with each other.

-It should be noted that springs r also transmit to pawl I3, through inclined surfaces I4" and I9, an effort in the same direction as F.

T'he system above described is both simple and eicient. I may also, with advantage, as shown by the drawing, give the breech block E a cross section in the form of an inverted T, the vertical branch of which extends between the branches of element "I, which is substantially fork-shaped.

In this case, I may, as shown by the drawing, provide a pawl I3 in each of the horizontal branches of the T. The corresponding notches I9 are formed in the under edges of forked shaped element 7 and notches I5 are provided in the bottom wall of casing 2, immediately behind aperture d.

Whatever be the specific arrangement that is chosen, such a system has the advantage that, when the head I4 of pawl I3 comes opposite notch I5 it is caught between two inclined surfaces 2i and I9", both of which are adapted to act on said head I for driving it into notch I5, so that this movement of head I4 is obtained more quickly and more safely than if it were subjected to the mere action of a single inclined surface or abutment.

Finally, the means for moving the breech structure in the rearward direction after the firing of a shot are so devised that element is rst moved toward the rear with respect to the breech block 6 so as to come back into engagement therewith. Then the cooperation of inclined surfaces IS and I'I causes pawl I3 to be brought back into the upper position, where it locks elements and 'I together. The rearward movement of the Whole is then ensured either by the means which have already produced the separate rearward movement of element I or, more simply and as it will be hereinafter supposed, under the effect of the pressure of the burnt powder gases transmitted through the metalrear end of the spent cartridge.

,In the example shown by the drawing, the means which start the rearward movement of element 1 so as to bring it back into engagement with element 6 consist of a piston and cylinder system 225 operated by the burnt powder gases present in the bore of the gun tube as soon as the projectile has travelled a certain distance inside said bore and thus uncovered an orice 2l.

With such an arrangement, immediately upon the shot being red, element I is pushed toward the rear through'the movable element of said piston and cylinder system. Then pawl I3 unlocks element I from with casing 2 and couples elements 6 and 'I together, the whole being caused to recoil by the action of the burnt powder gases.

This rearward movement of the lWhole of the movable breech structure under the effect of the pressure of the burnt powder gases compresses counterspring 5, which subsequently brings back the whole toward the front for the next shot.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and eicient embodiments of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition, and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An automatic firearm which comprises, in

combination, a tube, a. breech structure movable' at the rear thereof, a stationary casing rigidv with said tube for guiding said breech structure, said breech structure including a breech block proper and a firing pin carrier movable longitudinally to a limited extent with respect to said breech block, a pawl movably carried by said breech block, said ring pin carrier being provided with a notch adapted to cooperate with said pawl for interlocking said breech block and said ring pin carrier, the contacting surfaces of Vsaid pawl and said ring pin carrier being So inclined with respect to each other and with respect to the-direction of thrust as to produce a transverse component which tends to move said pawl transversely away from said notch, a guiding surface in said casing adapted to keep said pawl in said notch as long as said breech block has not reached the end of its frontward stroke, said guiding surface being provided with a notch adapted to receive said pawl pushed therein by the action of said component, and cooperating projections carried by said casing and said pawl respectively for driving said pawl away from the first mentioned notch and into the second mentioned notch when said breech block reaches the end of its frontward stroke.

2. An automatic firearm which comprises, in combination, a tube, a breech structure movablev with a reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure, said brech structure including a breech block proper and a firing pin carrier movable longitudinally to a limited extent with respect to said breech block, a pawl movably carried, by said breech block, saidfiring pin carrier being provided with a notch adapted to cooperate with said pawl for interlocking said breech block and said firing pin carrier, the contacting surfaces of said pawl and said firing pin carrier being so inclined with respect to each other and with respect to the direction of thrust as to produce a transverse component which tends to move said pawl transversely away from said notch, a guiding surface carried by said casing arranged to keep said pawl in said notch as long as said breech block has not reached the end of its frontward stroke, said guiding surface being provided with a notch adapted to receive said pawl pushed therein by the action of said component, cooperating projections carried bysaid casing and said pawl respectively for driving said pawl away from the first mentioned notch and into the second mentioned notch when said breech block reaches the end of its frontgvard stroke, thereby said pin carrier is disengaged from with said breech block and can further move forward, a counterspring for urging said firing pin carrier in the front- Ward direction, and means for returning said pawl to said rst mentioned notch comprising a projection carried by said pawl adapted to remain engaged in the first mentioned notch after the disengagement of said firing pin carrier and said breech block, and a projection carried by the front wall of the flrst mentioned notch adapted to cooperate with the last mentioned projection of said pawl, said projections, pawl, ring pin carrier, breech block, and notches being so adapted and arranged as to move said pawl out from the second mentioned notch and into the first mentioned notch at the beginning of the return movement of said fire pin carrier whereby to release said breech block from said casing and simultaneously to interlock said breech block and said firing pin carrier.

3. An automatic firearm which comprises, in combination, a tube, a breech structure, movable with a reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure, said breech structure including a breech block proper and a firing pin carrier movable longitudinallyv to a limited extent with respect to said breech block, a pawl movably carried by said breech block, said firing pin carrier being provided with a notch adapted to cooperatewith said pawl for interlocking said breech block and said ring pin carrier, the contacting surfaces of said pawl and said firing pin carrier being so inclined with respect to each other with respect to the direction of thrust as to produce a transverse component which tends to move said pawl transversely away from said notch, a part carried by said casing having a guiding surface for said pawl arranged to keep it engaged in said notch as long as said breech block has not reached the end of its frontward stroke, said guiding surface being provided with a notch adapted to receive said pawl pushed therein by the action of said component, cooperating projections carried by said casing and said pawl respectively for driving said pawl out from the first mentioned notch and into the second 'mentioned notch when said breech block reaches the end of its frontward stroke, whereby said pin carrier is disengaged from with said breech block and can further move forward, a counterspring for urging said firing pin. carrier in the frontward direction, and means, operative by the powder gases, from the gun tube, said means being so adapted and arranged as to drive back said firing pin carrier toward said breech block immediately after the firing of a shot in said gun, said means comprising a projection carried by said pawl adapted to remain engaged in the first mentioned notch after the disengagement of said ring pin carrier from with said breech block, and a projection carried by the front inner wall of the first mentioned notch adapted to cooperate With the last mentioned projection of said pawl for moving said pawl out from the second mentioned notch and into the rst mentioned notch at the beginning of the return movement of said firing pin carrier.

4. An automatic firearm according to claim 3 further including elastic means for urging said fire pin carrier frontwardly with respect to said breech block.

5. An automatic rearm which comprises, in combination, a tube, a breech structure movable with a reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure, said breech structure including a breech block proper and a firing pin carrier movable longitudinally to a limited extent with respect to said breech block, a pawl movably carried by said breech block, said firing pin carrier being provided with a notch adapted to cooperate with said pawl for interlocking said breech block and said firing pin carrier, the contacting surfaces of said pawl and said ring pin carrier being so inclinedvwith respectto each other and with respect to the direction of thrust as to produce a transverse component force which tends to move said pawl transversely out from said notch, a part carried by said casing having a guiding surface for said pawl arranged to keep it engaged in said notch as long as said breech block has not reached the end of its frontward stroke, said guiding surface lbeing provided with a notch adapted to receive said pawl pushed therein by the action of said component force, cooperating projections carried by said casing and said pawl respectively said projections being so adapted and arranged as to drive said pawl out from the first mentionedl notch and into the second mentioned notch when said breech block reaches the end of its frontward stroke, whereby said ring pin carrier is disengaged from with said breech block, said firing, pin carrier being so arranged with respect to said breech block and said casing that it is free to continue movement in the frontward direction when disengaged from the breech block and whereas said breech block is locked in firing position with respect to said casing, a count'erspring for urging said firing pin carrier in the frontward direction, and means comprising cooperating surfaces on said firing pin carrier and said catch, said surface being so arranged with `respect to the firing pin carrier and catch as to keep said pawl engaged in the second mentioned notch in locked position with respect to said casing during the displacement of said firing pin carrier subsequent to the locking of said breech block.

MARC BIRICIGT. 

